Histological differentiation between sporadic and colitis-associated intestinal cancer in a nationwide study: A propensity-score-matched analysis.

BACKGROUND AND AIM: Colitis-associated intestinal cancer (CAC) can develop in patients with inflammatory bowel disease; however, the malignant grade of CAC may differ from that of sporadic colorectal cancer (CRC). Therefore, we compared histological findings distinct from cancer stage between CAC and sporadic CRC to evaluate the features of CAC. METHODS: We reviewed the clinical and histological data collected from a nationwide database in Japan between 1983 and 2020. Patient characteristics were compared to distinguish ulcerative colitis (UC), Crohn's disease (CD), and sporadic CRC. Comparisons were performed by using all collected data and propensity score-matched data. RESULTS: A total of 1077 patients with UC-CAC, 297 with CD-CAC, and 136 927 with sporadic CRC were included. Although the prevalence of well or moderately differentiated adenocarcinoma (Tub1 and Tub2) decreased according to tumor progression for all diseases (P < 0.01), the prevalence of other histological findings, including signet ring cell carcinoma, mucinous carcinoma, poorly differentiated adenocarcinoma, or squamous cell carcinoma, was significantly higher in CAC than in sporadic CRC. Based on propensity score-matched data for 982 patients with UC and 268 with CD, the prevalence of histological findings other than Tub1 and Tub2 was also significantly higher in those with CAC. At pT4, mucinous carcinoma occurred at a significantly higher rate in patients with CD (45/86 [52.3%]) than in those with sporadic CRC (13/88 [14.8%]) (P < 0.01). CONCLUSION: CAC, including early-stage CAC, has a higher malignant grade than sporadic CRC, and this difference increases in significance with tumor progression.

Robotic-assisted colectomy for right-sided colon cancer: Short-term surgical outcomes of a multi-institutional prospective cohort study in Japan.

Background: In Japan, there are no substantial reports on robotic-assisted colectomy because few institutions performed the procedure, as it was not covered by national insurance until March 2022. Aim: This study aimed to evaluate the safety and feasibility of robotic-assisted colectomy for patients with curatively resectable colon cancer in Japan. Methods: This multi-institutional, prospective, single-arm, observational study enrolled patients diagnosed with curatively resectable clinical stage I-IIIC colon adenocarcinoma with D2 or D3 lymph node dissection and treated with robotic-assisted colectomy. The primary endpoint was the conversion rate to laparotomy. The non-inferiority of outcomes for robotic-assisted colectomy versus laparoscopic colectomy, which was determined from historical data, was verified. Results: One hundred patients were registered between July 2019 and March 2022 and underwent robotic-assisted colectomy performed by seven expert surgeons at six institutions. Thirteen patients were excluded because their surgeons had insufficient experience performing robotic-assisted colectomy; therefore, 87 patients were eligible for the primary endpoint analysis. There was no conversion in these 87 patients, and robotic-assisted colectomy was non-inferior to laparoscopic colectomy in terms of conversion rate (90% confidence interval 0-3.38, p = 0.0006). No intraoperative adverse events occurred, and no mortality was observed in a total of 100 patients. The rate of patients with Clavien-Dindo complications grade III or higher was 4%. Conclusion: This study showed the non-inferiority of the conversion rates between robotic-assisted colectomy and laparoscopic colectomy. Favorable perioperative outcomes also suggest the safety and feasibility of robotic-assisted colectomy.

[A Case of Locally Advanced, Unresectable Pancreatic Cancer with Superior Mesenteric Artery Invasion Treated with FOLFIRINOX plus Radiation Therapy, followed by Conversion Surgery].

We report a case of a woman in her 70s who underwent conversion surgery after FOLFIRINOX, followed by radiation therapy for initially locally advanced unresectable pancreatic cancer. She visited her local doctor with a chief complaint of upper abdominal pain. Contrast-enhanced CT scan of the abdomen revealed an irregular mass invading the superior mesenteric artery, and the first and second jejunal arteries(>180°)in the pancreatic uncinate region. Based on imaging, she was diagnosed as UR-LA(sm), cT4N0M0, cStage Ⅲ pancreatic cancer, and underwent 5 courses of modified FOLFIRINOX. Radiation therapy of 50.4 Gy was added for local control, and CA19-9 decreased from 394.1 U/mL to 10.5 U/mL. The treatment effect was judged as RECIST: partial response. The tumor was considered to be potentially curative, and a subtotal stomach preserving pancreaticoduodenectomy was performed 8 months after the initial treatment. The tumor was found to be 3× 2 mm in size, pStage ⅠA, R0, and the response to preoperative chemotherapy: Evans Grade Ⅲ. The patient is alive at 5 months postoperatively without recurrence.

[A Case of Local Recurrent Liver Metastasis from Sigmoid Colon Cancer after Complete Histological Remission, Treated with Rehepatectomy].

We report a case of a patient with sigmoid colon cancer and multiple liver metastases who underwent hepatectomy after chemotherapy and pathological results showed complete remission. However, after chemotherapy was discontinued, the patient developed a local recurrence of the liver metastasis and underwent rehepatectomy. The patient came to our hospital with lower abdominal pain. Colonoscopy revealed a circumferential type Ⅱ, well-differentiated adenocarcinoma. Laparoscopic sigmoidectomy with lymph node dissection was performed. Postoperative CT scan showed multiple liver metastases at S5, S7, and S8. 11 cycles of bevacizumab plus modified FOLFOX(mFOLFOX)were subsequently performed. The liver metastases shrank at all sites, and the patient underwent right hepatectomy. The resected specimen was considered to be in complete remission, with no evidence of viable malignant cells. Postoperatively, bevacizumab plus mFOLFOX was resumed for 6 cycles and the patient remained in remission. However, 3 months after stopping chemotherapy and 1 year and 6 months after hepatectomy, a follow-up CT scan showed local recurrence of the liver edge, and a diagnosis of local recurrence of liver metastasis was made, and a partial hepatectomy was performed. The patient is recurrence-free and resuming modified FOLFOX 9 months after surgery.

Crohn's Disease-Associated Anorectal Cancer Has a Poor Prognosis With High Local Recurrence: A Subanalysis of the Nationwide Japanese Study.

INTRODUCTION: Colorectal cancer (CRC) is one of the major life-threatening complications in patients with Crohn's disease (CD). Previous studies of CD-associated CRC (CD-CRC) have involved only small numbers of patients, and no large series have been reported from Asia. The aim of this study was to clarify the prognosis and clinicopathological features of CD-CRC compared with sporadic CRC. METHODS: A large nationwide database was used to identify patients with CD-CRC (n = 233) and sporadic CRC (n = 129,783) over a 40-year period, from 1980 to 2020. Five-year overall survival (OS), recurrence-free survival (RFS), and clinicopathological characteristics were investigated. The prognosis of CD-CRC was further evaluated in groups divided by colon cancer and anorectal cancer (RC). Multivariable Cox regression analysis was used to adjust for confounding by unbalanced covariables. RESULTS: Compared with sporadic cases, patients with CD-CRC were younger; more often had RC, multiple lesions, and mucinous adenocarcinoma; and had lower R0 resection rates. Five-year OS was worse for CD-CRC than for sporadic CRC (53.99% vs 71.17%, P < 0.001). Multivariable Cox regression analysis revealed that CD was associated with significantly poorer survival (hazard ratio 2.36, 95% confidence interval: 1.54-3.62, P < 0.0001). Evaluation by tumor location showed significantly worse 5-year OS and RFS of CD-RC compared with sporadic RC. Recurrence was identified in 39.57% of CD-RC cases and was mostly local. DISCUSSION: Poor prognosis of CD-CRC is attributable primarily to RC and high local recurrence. Local control is indispensable to improving prognosis.

Effect of Biologics on the Risk of Advanced-Stage Inflammatory Bowel Disease-Associated Intestinal Cancer: A Nationwide Study.

INTRODUCTION: The aim of this study was to evaluate the effect of biologics on the risk of advanced-stage inflammatory bowel disease (IBD)-associated intestinal cancer from a nationwide multicenter data set. METHODS: The medical records of patients with Crohn's disease (CD) and ulcerative colitis (UC) diagnosed with IBD-associated intestinal neoplasia (dysplasia or cancer) from 1983 to 2020 were included in this study. Therapeutic agents were classified into 3 types: biologics, 5-aminosalicylic acid, and immunomodulators. The pathological cancer stage was compared based on the drug used in both patients with CD and UC. RESULTS: In total, 1,042 patients (214 CD and 828 UC patients) were included. None of the drugs were significantly associated with cancer stage in the patients with CD. In the patients with UC, an advanced cancer stage was significantly associated with less use of biologics (early stage: 7.7% vs advanced stage: 2.0%, P < 0.001), 5-aminosalicylic acid, and immunomodulators. Biologic use was associated with a lower incidence of advanced-stage cancer in patients diagnosed by regular surveillance (biologics [-] 24.5% vs [+] 9.1%, P = 0.043), but this was not the case for the other drugs. Multivariate analysis showed that biologic use was significantly associated with a lower risk of advanced-stage disease (odds ratio = 0.111 [95% confidence interval, 0.034-0.356], P < 0.001). DISCUSSION: Biologic use was associated with a lower risk of advanced IBD-associated cancer in patients with UC but not with CD. The mechanism of cancer progression between UC and CD may be different and needs to be further investigated.

Long-term results of minimally invasive transanal surgery for rectal tumors in 249 consecutive patients.

PURPOSE: To delineate the long-term results of minimally invasive transanal surgery (MITAS) for selected rectal tumors. METHODS: We analyzed data, retrospectively, on consecutive patients who underwent MITAS between 1995 and 2015, to establish the feasibility, excision quality, and perioperative and oncological outcomes of this procedure. RESULTS: MITAS was performed on 243 patients. The final histology included 142 cancers, 47 adenomas, and 52 neuroendocrine tumors (NET G1). A positive margin of 1.6% and 100% en bloc resection were achieved. The mean operative time was 27.4 min. Postoperative morbidity occurred in 7% of patients, with 0% mortality. The median follow-up was 100 months (up to ≥ 5 years or until death in 91.8% of patients). Recurrence developed in 2.9% of the patients. The 10-year overall survival rate was 100% for patients with NET G1 and 80.3% for those with cancer. The 5-year DFS was 100% for patients with Tis cancer, 90.6% for those with T1 cancer, and 87.5% for those with T2 or deeper cancers. MITAS for rectal tumors ≥ 3 cm resulted in perioperative and oncologic outcomes equivalent to those for tumors < 3 cm. CONCLUSION: MITAS is feasible for the local excision (LE) of selected rectal tumors, including tumors ≥ 3 cm. It reduces operative time and secures excision quality and long-term oncological outcomes.

Clinical features and oncological outcomes of intestinal cancers associated with ulcerative colitis and Crohn's disease.

BACKGROUND: Patients with longstanding inflammatory bowel disease are at high risk of developing intestinal cancers. In this study, we aimed to elucidate the differences between intestinal cancers associated with ulcerative colitis and Crohn's disease. METHODS: Intestinal cancers in ulcerative colitis and Crohn's disease patients treated between 1983 and 2020 at 43 Japanese institutions were retrospectively analyzed.. RESULTS: A total of 1505 intestinal cancers in 1189 ulcerative colitis and 316 Crohn's disease patients were studied. Almost all of ulcerative colitis-associated cancers (99%) were in the colon and rectum, whereas half of Crohn's disease-associated cancers (44%) were in the anus, with 11% in the small intestine. Ulcerative colitis-associated cancers were diagnosed more frequently by surveillance (67% vs. 25%, P < 0.0001) and at earlier stages (stages 0-1, 71% vs. 27%, P < 0.0001) compared with Crohn's disease-associated cancers. Colorectal cancers associated with Crohn's disease showed a significantly worse 5-year overall survival rate than those associated with ulcerative colitis (stage 2, 76% vs. 89%, P = 0.01, stage 3, 18% vs. 68%, P = 0.0009, and stage 4, 0% vs. 13%, P = 0.04). Surveillance correlated with earlier diagnoses for ulcerative colitis- and Crohn's disease-associated intestinal cancers, whereas shorter intervals between endoscopic examinations correlated with an earlier cancer diagnosis in ulcerative colitis patients but not in Crohn's disease patients. CONCLUSIONS: The clinical and oncological features of ulcerative colitis- and Crohn's disease-associated cancers were very different. Crohn's disease-associated cancers were diagnosed at more advanced stages and were detected less frequently by surveillance. Additionally, they showed a significantly poorer prognosis.

Japanese multicenter prospective study investigating laparoscopic surgery for locally advanced rectal cancer with evaluation of CRM and TME quality (PRODUCT trial).

Aim: In Japan, we have not been able to validate the results of laparoscopic surgery for locally advanced rectal cancer using the universal index "circumferential resection margin (CRM)." Previously, we established a semi-opened circular specimen processing method and validated its feasibility. In the PRODUCT trial, we aimed to assess CRM in patients with locally advanced rectal cancer who underwent laparoscopic rectal resection. Methods: This was a multicenter, prospective, observational study. Eligible patients had histologically confirmed rectal adenocarcinoma located at or below 12 cm above the anal verge with clinical stage II or III and were scheduled for laparoscopic or robotic surgery. The primary endpoint was pathological CRM. CRM ≤1 mm was defined as positive. Results: A total of 303 patients operated on between August 2018 and January 2020 were included in the primary analysis. The number of patients with clinical stage II and III was 139 and 164, respectively. Upfront surgery was performed for 213 patients and neoadjuvant therapy for 90 patients. The median CRM was 4.0 mm (IQR, 2.1-8.0 mm), and CRM was positive in 26 cases (8.6%). Univariate and multivariate analyses demonstrated that a predicted CRM from the mesorectal fascia of ≤1 mm on MRI was the significant factor for positive CRM (P = .0012 and P = .0045, respectively). Conclusion: This study showed the quality of laparoscopic rectal resection based on the CRM in Japan. Preoperative MRI is recommended for locally advanced rectal cancer to prevent CRM positivity.

Differential analysis of microbiomes in mucus and tissues obtained from colorectal cancer patients.

The outer mucus layer of the colorectal epithelium is easily removable and colonized by commensal microbiota, while the inner mucus layer is firmly attached to the epithelium and devoid of bacteria. Although the specific bacteria penetrating the inner mucus layer can contact epithelial cells and trigger cancer development, most studies ignore the degree of mucus adhesion at sampling. Therefore, we evaluated whether bacteria adhering to tissues could be identified by removing the outer mucus layer. Our 16S rRNA gene sequencing analysis of 18 surgical specimens of human colorectal cancer revealed that Sutterella (P = 0.045) and Enterobacteriaceae (P = 0.045) were significantly enriched in the mucus covering the mucosa relative to the mucosa. Rikenellaceae (P = 0.026) was significantly enriched in the mucus covering cancer tissues compared with those same cancer tissues. Ruminococcaceae (P = 0.015), Enterobacteriaceae (P = 0.030), and Erysipelotrichaceae (P = 0.028) were significantly enriched in the mucus covering the mucosa compared with the mucus covering cancers. Fusobacterium (P = 0.038) was significantly enriched in the mucus covering cancers compared with the mucus covering the mucosa. Comparing the microbiomes of mucus and tissues with mucus removed may facilitate identifying bacteria that genuinely invade tissues and affect tumorigenesis.

Usefulness of vacuum-assisted closure after stoma closure with purse string suturing: a retrospective trial.

Objectives: Surgical site infection (SSI) is a problematic complication after stoma closure. The purse string suture (PSS) technique eliminates this problem, but the area takes longer to heal. The present retrospective study was performed to evaluate the usefulness of a vacuum-assisted closure (VAC) system for the promotion of wound healing after stoma closure. Methods: Consecutive patients undergoing stoma closure with the PSS technique were divided into two groups: those treated with and without use of the VAC system. The volume of dead space and the size of the wound were measured after stoma closure in both groups. The same measurements were performed on days 3 and 7 after closure. The time needed for wound closure was also examined in both groups. Outcomes were also evaluated according to age, body mass index, operative time, bleeding volume, wound consistency, patient satisfaction, perioperative inflammatory response, occurrence of SSI, and hospitalization days. Results: The VAC group comprised 31 patients, and the non-VAC group comprised 34 patients. The volume of dead space on days 3 and 7 after closure was significantly smaller in the VAC group than in the non-VAC group (P=0.006 and P<0.001, respectively). The number of SSIs was significantly lower in the VAC group than in the non-VAC group (P=0.014). Conclusion: The dead space volume on days 3 and 7 after stoma closure with PSS significantly decreased by using the VAC system. The incidence of SSI after stoma closure also significantly decreased by using the VAC system.

Establishment of the menthol test as a clinical evaluation method for oxaliplatin-induced neuropathy.

Objectives: To determine whether the tongue menthol test, which measures the cold sensation detection threshold (CDT) of the tongue, used before and after oxaliplatin administration is an objective evaluation method for oxaliplatin-induced peripheral neuropathy (OPN). Methods: The tongue menthol test was administered to patients both before and after undergoing chemotherapy containing oxaliplatin for colorectal cancer. The tongue menthol test was conducted by applying a menthol solution (a selective agonist of transient receptor potential cation channel subfamily M member 8 [TRPM8]) to the tongue and measuring the CDT. Results: The mean CDT before the first dose of oxaliplatin was 0.34% (0.005%-1%; n=38), and the mean CDT after the first dose was 0.32% (0.005%-1%; n=38). The CDT appeared to decrease after the first dose, but this difference was not significant. In patients who received five courses of oxaliplatin, changes in CDT values were compared before and after the five courses. In patients with Neurotoxicity Criteria of Debiopharm (DEB-NTC) grade 2 neuropathy, the pre-oxaliplatin administration CDT was compared between before grade exacerbation and when exacerbation occurred, and was found to decline when grade exacerbation occurred. Moreover, when the CDTs before and after administration were compared before grade exacerbation, there was a significant decrease in CDT after administration (P=0.04). Conclusions: By performing a menthol test in oxaliplatin-treated patients, it may be possible to objectively predict the exacerbation of peripheral neuropathy at an early stage.

The double bipolar method for robotic total mesorectal excision in patients with rectal cancer.

Although meta-analyses and systematic reviews have clarified the benefits of robotic surgery, few studies have focused on robotic rectal surgery (RRS) and the use of Endowrist® instruments. Therefore, we evaluated RRS using the double bipolar method (DBM) and compared its short-term outcomes with those of RRS using the single bipolar method (SBM). This study enrolled 157 consecutive patients and all procedures were performed by the same surgeon and recorded through short video clips. We analyzed the patient demographics and short-term clinical outcomes. Although this observational study has several limitations, the console time for total mesorectal excision using the DBM was significantly shorter than that using the SBM. Although the DBM did not demonstrate a specific learning curve, it was a safe and feasible procedure even for patients with advanced disease. Further studies are needed to evaluate the cost-effectiveness of the DBM.

Usefulness of laparoscopic right colectomy with intracorporeal anastomosis and preoperative weight reduction for ascending colon cancer in a severely obese patient.

Obesity has been considered a risk factor for postoperative complications following colorectal cancer surgery. However, the usefulness of a combination of intracorporeal anastomosis and preoperative weight reduction for severely obese patients with colon cancer remains unclear. A 66-year-old man with a body mass index (BMI) of 43 kg/m2 presented with abdominal pain and iron deficiency anemia. Colonoscopy and computed tomography revealed advanced ascending colon cancer with regional lymph node metastasis and excessive abdominal fat. Preoperative diet-induced weight reduction was performed for severe obesity, which decreased his BMI to 39.7 kg/m2 after 1 month. Thereafter, curative resection was performed using intracorporeal anastomosis for reconstruction to achieve minimal colon and mesentery mobilization and a shorter incision. The patient was discharged from the hospital without complications. Laparoscopic right hemicolectomy combining intracorporeal anastomosis and preoperative weight reduction was extremely useful in the current patient with severe obesity and ascending colon cancer.

Prevalence and Risk Factors of Anal and Fecal Incontinence in Japanese Medical Personnel.

OBJECTIVES: This study aimed to elucidate the actual state of anal incontinence (AI), fecal incontinence (FI), and the associated factors in Japanese medical personnel. METHODS: A questionnaire was completed by Japanese medical personnel after listening to lectures on AI. AI was defined as involuntary loss of feces or flatus. RESULTS: A total of 463 persons (mean age, 35.6 years; range, 20-91; male/female/no answer, 132/324/7) participated in the questionnaire. AI occurred in 34.4% of 450 participants (flatus/liquid stool/solid stool: 30.4%/3.6%/0.4%). AI was significantly more prevalent in females (male/female: 15.5%/42.7%, p < 0.001). AI and FI occurred significantly more prevalent in participants aged ≧40 years (p < 0.024). AI was significantly associated with childbirth, frequency of childbirth (more than three times), vaginal delivery, urinary incontinence, the style of urination/defecation, and a history of gynecologic surgery and systemic diseases (p < 0.05). Female gender and age as well as urinary incontinence and inability to defecate separately in female and previous colorectal disease and/or surgery in male were risk factors of AI by multivariate analysis (p < 0.05). FI was correlated with urinary incontinence. CONCLUSIONS: AI and FI occurred in 34.4% and 4.0% of Japanese medical personnel, respectively. Gas incontinence was common in every age group. AI was associated with female gender, higher age group, urinary incontinence, the style of urination and defecation in female, and previous colorectal disease and/or surgery in male. FI was associated with urinary incontinence.

Erratum for Questionnaire Survey of Bowel Habit in Japanese Medical Personnel.

[This corrects the article DOI: 10.23922/jarc.2021-014.].

Questionnaire Survey of Bowel Habit in Japanese Medical Personnel.

OBJECTIVES: This study aims to clarify the bowel habit, change of bowel movement throughout the cycle of menstruation, and toilet use in Japanese medical personnel. METHODS: A questionnaire survey was completed by Japanese medical personnel after listening to lectures on bowel disorders. Constipation was defined according to Rome III criteria, whereas diarrhea was defined as Bristol stool form scale type 6 and 7. RESULTS: In total, 463 persons (mean age, 35.6 years, range 20-91, male/female/no answer: 132/324/7) have completed the questionnaire. Constipation was significantly more often observed in females (male/female: 3%/31%, p > 0.001, Chi-squared test), while diarrhea was noted to be less in females (male/female: 1%/7%). Constipation was observed in 20% of participants in their 20s, and the constipation rate was observed to gradually increase with age. It was observed in 45% of participants in their 70s or older. Bowel movement changed to constipation around menstruation in 18% of females and changed to diarrhea in 43% of females. Constipation often occurred before menstruation and diarrhea during menstruation. Only 2% of participants used a Japanese-style toilet, and 5% of participants claimed that they were unable to pass a stool on a Japanese-style toilet. CONCLUSIONS: Constipation was significantly more frequent in females and increased with age among female Japanese medical personnel. Change of bowel movement occurred in 61% of females around menstruation. Five percent of participants were unable to pass stools on a Japanese-style toilet.

Outcomes of Transvaginal Anterior Levatorplasty with Posterior Colporrhaphy for Symptomatic Rectocele.

OBJECTIVES: To clarify the long-term outcomes of transvaginal anterior levatorplasty with posterior colporrhaphy for symptomatic rectocele with defecographic changes. METHODS: Consecutive patients undergoing transvaginal anterior levatorplasty with posterior colporrhaphy for symptomatic rectocele were prospectively registered and retrospectively reviewed using medical records. Symptoms, fecal incontinence, and defecographic findings were evaluated before and after surgery. RESULTS: Fifty-seven women (mean age, 68 years) were identified, and the median disease duration was 24 months. Symptoms of vaginal mass (n = 32) and difficult defecation (n = 21) disappeared (90.6% and 71.4%, respectively) or improved (6.3% and 28.6%, respectively) after surgery. However, the feeling of residual stool was unchanged in two of eight patients. Seventeen patients who performed digitation on defecation before surgery discontinued digitation after surgery. The proportion of patients who had fecal incontinence preoperatively (40.4%) decreased significantly after surgery (17.5%) during a median follow-up period of 47 months. Defecography revealed a disappearance or improvement of rectocele in all 18 patients examined. The average rectocele size decreased significantly in six improved patients (p = 0.0006, paired t-test). CONCLUSIONS: Transvaginal anterior levatorplasty with posterior colporrhaphy for symptomatic rectocele was a useful option to improve symptoms and anatomical disorders in the long term, but it had limitations in improving defecatory symptoms.

Robotic low anterior resection for rectal cancer with side-to-end anastomosis in a patient with anal stenosis.

BACKGROUND: Colorectal anastomosis using the double stapling technique (DST) has become a standard procedure. However, DST is difficult to perform in patients with anal stenosis because a circular stapler cannot be inserted into the rectum through the anus. Thus, an alternative procedure is required for colorectal anastomosis. CASE PRESENTATION: A 78-year-old woman presented with bloody stool. Colonoscopy and computed tomography revealed advanced low rectal cancer without lymph node or distant metastasis. We initially planned to perform low anterior resection using a double stapling technique or transanal hand-sewn anastomosis, but this would have been too difficult due to anal stenosis and fibrosis caused by a Milligan-Morgan hemorrhoidectomy performed 20 years earlier. The patient had never experienced defecation problems and declined a stoma. Therefore, we inserted an anvil into the rectal stump and fixed it robotically with a purse-string suture followed by insertion of the shaft of the circular stapler from the sigmoidal side. In this way, side-to-end anastomosis was accomplished laparoscopically. The distance from the anus to the anastomosis was 5 cm. The patient was discharged with no anastomotic leakage. Robotic assistance proved extremely useful for low anterior resection with side-to-end anastomosis. CONCLUSION: Performing side-to-end anastomosis with robotic assistance was extremely useful in this patient with rectal cancer and anal stenosis.